Iran's chief negotiator, Abbas Araqchi, said that his country "has made good and tangible progress on various issues in the Vienna negotiations."
On the other hand, European sources confirmed that the negotiations are proceeding regardless of the course of the Iranian elections.
Araqchi added - in exclusive statements to Al Jazeera - that he believes that Iran is closer to an agreement than ever before, but "there are still basic issues that we will negotiate on."
The Iranian chief negotiator stressed that each party must take difficult measures, and that his country made the difficult decision to remain in the agreement despite Washington's departure.
Araqchi stressed that the elections have no effect on the progress of the negotiations, saying, "We are negotiating regardless of our internal policy, and when we get a good agreement we will agree to it, otherwise there is no agreement with this government or the next government."
He added, "Iran has suffered over the past years because of the US withdrawal from the nuclear agreement, and we want to make sure that what happened with (former President Donald) Trump's withdrawal from the agreement, will not be repeated with any US president in the future."
European optimism
In turn, Enrique Mora, the representative of the European Union, expressed his belief that these negotiations will succeed in reaching an agreement.
European sources close to the Vienna negotiations said, "The European Union deals with these negotiations as with the Iranian state, and not with a government or an outgoing or incoming president."
These sources mentioned - to Al-Jazeera correspondent - that there are still differences, but negotiation is enough to resolve them.
For its part, the French Foreign Ministry said, "The negotiations are going through a difficult stage, as they are addressing at this time complex issues, and difficult differences that are still ongoing."
"Negotiations have become more difficult, with access to discussing issues," which she described as complex, and "Important points of contention still exist, and courageous decisions must be taken quickly because time is not on anyone's side," French Foreign Ministry spokeswoman Agnes von der Muhll said in a statement.
Rafael Grossi, Director-General of the International Atomic Energy Agency of the United Nations, said on Tuesday, "The ongoing negotiations in Vienna for weeks have dealt with very complex and sensitive technical issues, but what is required is the political will of all parties."
"Everyone knows that, at this point, it will be necessary to wait for the new Iranian government," Grossi said in an interview with La Repubblica newspaper, in response to a question about the stage of the talks on reviving the agreement.